1. Field of the Invention
This invention relates generally to flexible seals for bearing applications, and is concerned in particular with a flexible lip seal of the type employed in rolling mill oil film bearings.
2. Description of the Prior Art
One example of a prior art seal design is disclosed in U.S. Pat. No. 2,868,574, wherein a seal is surrounded by a stationary circular seal end plate having a radially inwardly extending rigid flange separating oppositely arranged shoulders. The flexible seal has radially outwardly extending flexible flanges which are in sliding contact with inclined surfaces on the shoulders of the seal end plate. The flange/shoulder surface interface on the inboard side serves to retain bearing lubricant in the bearing, and the flange/shoulder surface interface on the outboard side serves to exclude contaminants such as cooling water, mill scale, etc. from penetrating into the bearing.
This design exhibits problems such as leakage of the bearing lubricant, contaminant entering the bearing chamber and excessive wear of the seal components. These problems are due in large part to the seal flanges which are thick and heavy throughout their length. Therefore, the flanges are not as flexible as they should be and have a tendency to become distorted and fail to provide an effective seal.
In the seal design disclosed in U.S. Pat. No. 4,165,881, these problem were addressed by providing the seal flanges with peripheral relatively thin flexible lips. This design resulted in improved sealing performance, but leakage problems persisted when the seal was not properly aligned with respect to the seal end plate.
A need has continued to exist, therefore, for a seal that can operate effectively under all operating conditions, including those in which the seals are improperly aligned with respect to the seal end plates.